1. Field of the Invention
The present invention relates to a steering controller for a movable robot. More specifically, the present invention relates to a steering controller that allows an operator to intuitionally steer a movable robot, a steering control method using the steering controller, and a movable robot system using the steering controller.
2. Description of the Related Art
Dangerous materials (e.g., gases) flowing through pipes make it difficult to inspect the internal state of the pipes. Further, impurities present within indoor water supply pipes (particularly, old pipes) are difficult to remove owing to the limited diameter of the pipes.
Under these circumstances, there is an urgent need to develop equipment that can remove impurities within pipelines and repair old pipelines while real-time inspecting the internal state of the pipelines irrespective of the material danger and the limitation of small diameter.
There have been many research efforts on developing movable robots that can inspect the internal state of pipelines as specific and limited three-dimensional spaces while moving in the pipelines. Such pipeline inspection movable robots are currently under study.
However, most of the studies on pipeline inspection movable robots have focused on moving the movable robots in close contact with pipelines while maintaining the bodies of the movable robots stable in order to allow the movable robots to move smoothly in the pipelines, achieving improved motion capability of the movable robots.
A pipeline inspection movable robot essentially moves in pipelines equipped with elbows or T-branches. It is not easy to steer the motion of the pipeline inspection movable robot in a desired direction when passing through the nonlinear connection portions.
Particularly, when an operator intends to move a differential-driven pipeline inspection movable robot including three powered wheel chains arranged at angular angles of 120° with respect to each other in a bent pipeline portion, the movable robot is driven in such a manner that the rotational velocity of at least one wheel increases while stopping the other wheel(s) depending on the rotational direction. To this end, the operator recognizes the geometric shape of the pipeline and directly controls the rotational velocities of the wheels in an on-off fashion to steer the movable robot in the bent portion.
This steering method based on on-off control does not cause significant damage to a movable robot moving at a low speed, but it may cause damage to a movable robot (including motors) when the movable robot moves with a large radius of curvature or at a high speed in a pipeline. Further, the on-off steering control method involves directly controlling the rotational velocities of the motors depending on the shape of the bent portion, causing inconvenience and slow speed in steering.